A.V.Jan 7, 2025
John Carlos Baez

Is fundamental physics really experiencing a Great Stagnation? In this thread, let's look at the history of fundamental physics from the dawn of the 20th century to now.

Experimental discoveries that were later accounted for by theories will be shown in yellow. (Mustard?)

Theoretical predictions that that were later confirmed by experiment are in green.

Experiments that confirmed theoretical predictions are in black.

Experiments that are still not accounted for by theories are shown in red.

(Yes, I'm a theorist. So to me, green means "success!" while red means "hey, we gotta do something here!)

One could argue endlessly about what to put on this list, and also what counts as "fundamental" physics. To me, the "fundamental" laws of physics are those that *in principle* we could use to compute all the physical quantities that we can compute at all.

The words "in principle' are carrying a lot of weight here. There are many laws, like formulas for turbulent fluid flow or masses of short-lived particles made of quarks, that we can't yet derive from the so-called "fundamental" laws. Yet most physicists think these are just signs of limitations in our ability to work with the fundamental laws, not new fundamental laws.

There is a long conversation to be had here about computability, chaos, etc. But that's not what these posts are about! Let's go back to the turn of the 20th century, and see how fundamental physics has grown since then.

Actually we should start in 1897.

(1/n)

Jan 5, 2025 at 5:20pmWeb
Show threadJohn Carlos BaezJan 5, 2025

The really shocking thing is how much the first two decades of fundamental physics in 20th century were dominated by one man: Einstein.

In the same year he predicted that light was made of particles, showed how to prove that matter was made of atoms, and unified space and time.

After thinking for a decade more, he gave a precise formula explaining gravity as the *curvature* of space and time, and predicted that gravity could form waves.

The two really big experimental surprises in this era are shown in yellow. In 1897, J. J. Thomson discovered electrons, and in 1911 Rutherford's team discovered that every atom has a small heavy central core.

(2/n)

Show threadJohn Carlos BaezJan 5, 2025

The period from 1920 to 1940 was just as explosive in fundamental physics.

In 1922, Friedmann used Einstein's theory of gravity to predict that the universe is expanding: galaxies are moving away from each other. In just 4 years this was confirmed by Hubble!

Einstein's predicted particles of light were found in 1923 and eventually called 'photons'.

But the biggest revolution occurred around 1925, when Schrödinger, Heisenberg, Born, Jordan, Dirac and others discovered that most of the universe was governed by linear algebra. This new way of understanding physics is called 'quantum mechanics'. One of its first big successes was computing the spectrum of light emitted by hydrogen, but thousands more came soon.

Then in orange we see a bunch of shocking experimental discoveries that eventually fit into the Standard Model... and one in red that we *still* don't understand!

(3/n)

Show threadJohn Carlos BaezJan 5, 2025

In fundamental physics, the period from 1940 to 1960 looks a bit slower than the previous two decades. Perhaps World War II slowed things down.

But the development of quantum electrodynamics was huge. People had been trying for decades to unify quantum mechanics with special relativity - that is, understand a world where space and time are unified and all particles and forces are described using linear algebra. Initial attempts gave infinite answers to physics questions.

Only when Tomonaga, Schwinger and Feynman developed "renormalization" did this project begin to succeed. At first it only applied to charged particles interacting by exchanging photons. This is called quantum electrodynamics. But this opened the floodgates for future work on quantum field theory.

Pauli had predicted there must be a hard-to-detect and almost massless particle which he called the "neutrino". This was found in 1956. It turned out to be just the first of three.

And also in 1956, a huge experimental shocker: Wu discovered that left and right are fundamentally different!

(4/n)

Show threadJohn Carlos BaezJan 5, 2025

The period from 1960 to 1980 was the heyday of particle physics! This is when I was a kid, so you can see I wanted to work on fundamental physics.

There was a thrilling interplay of theory and experiment. There were plenty of experimental surprises that were later fit into the Standard Model (in yellow), but also brand-new theories, now parts of the Standard Model, that were later confirmed by experiment (in green).

The 2nd neutrino came as a surprise, but the first 3 quarks were predicted to exist, by Gell-Mann, Zweig and others, based on data about the zoo of particles (made of quarks) that were being discovered. Electromagnetism was unified with the weak nuclear force in a theory that predicted the W, Z and Higgs bosons. Then 3 more quarks were predicte - and people came up with a theory of the strong nuclear force that holds together quarks, saying that it's carried by bosons of its own, jokingly called gluons.

The biggest experimental surprise in this era is the discovery that not only is left different from right, the world also change if you could switch left and right while switching matter and antimatter. This is called the violation of CP symmetry. This too is now a key part of the Standard Model.

You'll notice that, despite all this excitement, physicists were starting to probe realms very far from everyday human experience. Unlike work down in the first half of the century, it's hard to use these theories to build new technologies. The low-hanging fruit had already been picked when it comes to finding new fundamental laws. By this time, most physics was about *applying* the laws we already knew.

(5/n)

Show threadJohn Carlos BaezJan 5, 2025

The gusher of new fundamental physics slowed in 1980.

Indeed, from this time on we don't see anything in yellow or green - that is, new experimental discoveries that by now are well understood theoretically, or new fundamental theories that have by now been confirmed by experiment. This is what I call the Great Stagnation.

Instead, what we see are confirmations of old theories, in black, and experimental surprises that we still don't fully understand, in red. Of course the red stuff is not necessarily bad! This is where we can hope for new progress. Most of it comes from astronomy.

I personally feel the new slightly tweaked Standard Model with Dirac masses for neutrinos will correctly account for how neutrinos "oscillate" - that is, switch back and forth between different kinds. But the jury is still out out on that.

The accelerating expansion of the universe came as a huge surprise back in 1998 when it was discovered by two independent teams, the Supernova Cosmology Project and the High-Z Supernova Search Team. By now we have lots more data on this, but people still argue about it a lot as each new experiment comes in. The simplest theory of accelerating expansion goes back to Einstein and DeSitter: a "cosmological constant" giving empty space a constant negative pressure and positive energy density. It's also called "dark energy".

But physicists can make up theories where the dark energy is getting stronger with time, or weaker. So some claim the acceleration is increasing, while others claim it's decreasing. You see lots of stories about this in the pop science news. Take them with a big grain of salt. Better experiments are coming.

(6/n)

Show threadJohn Carlos BaezJan 5, 2025

By 2000 the Great Stagnation in fundamental physics was well underway.

Yes, the discovery of the Higgs boson was a great triumph of experimental physics. But in the grand scheme of things, it was like finding your wallet on your desk where you knew you must have left it.

I didn't even list the detection of gravitational waves by LIGO and Virgo in 2016. This is a bit brutal, but I already listed 1981 as the year when Hulse and Taylor discovered that a binary pulsar is emitting gravitational waves just as predicted by Einstein's theory. So by 2016, we all knew gravitational waves *existed*. The interesting part was becoming able to detect them well enough to start using them as a tool in astronomy! And this has been great: we're discovering a lot of surprises. But not - yet - new fundamental laws.

I also haven't listed all the new observations concerning dark matter, or whatever is making galaxies spin faster than we'd expect. The original discovery goes back to 1933. What we are doing now is collecting more and more data... which so far is making the mystery ever more intriguing and mysterious. So this is not stagnation by any means. But we have not found the fundamental laws that explain what's going on.

What does it all mean? I have plenty of thoughts, but today I just wanted to review the arc of fundamental physics since 1897, in a very crude outline.

(7/n, n = 7)

Show thread2xfoJan 5, 2025

@johncarlosbaez

I've been seeing a new theory that says matter causes time to pass at different rates. Supposedly it explains the problem that leads to the dark matter theory. Apparently the universe may actually older in some parts than it is in others so there's no missing energy, we were just looking at it with incorrect assumptions.

Show threadBartosz MilewskiJan 5, 2025
@RnDanger @johncarlosbaez
The timescape theory
Show threadmyxJan 5, 2025
@BartoszMilewski @RnDanger @johncarlosbaez @startswithabang.bsky.social is not impressed: https://bigthink.com/starts-with-a-bang/lumpy-explain-dark-energy/
Ask Ethan: Can a lumpy Universe explain dark energy?

Our Universe isn't just expanding, the expansion is accelerating. Instead of dark energy, could a "lumpy" Universe be at fault?

Big Think
Show threadBartosz MilewskiJan 5, 2025
@myx @RnDanger @johncarlosbaez @startswithabang.bsky.social
It's hard to tell without getting into all the details. The problem is that observational data are always mixed with simulations. We know that the CMD is very uniform. But does it mean that the Universe as it is now is uniform? To find out, we have to run our models, which assume the presence of dark energy. And it's not a binary choice: there could be both a non-zero cosmological constant and the large-scale timescape.
Show threadManuJan 5, 2025
@RnDanger @johncarlosbaez I think this is the paper you are referring to: https://academic.oup.com/mnrasl/article/537/1/L55/7926647?login=false
Show thread2xfoJan 5, 2025
@nu @johncarlosbaez
The things I've seen about it probably referenced that, yes 😅
Show threadTobyBartelsJan 5, 2025
@RnDanger @johncarlosbaez : Timescape cosmology. It goes back at least to 2008, but it's been in the news recently because of some papers this month claiming that it fits observation better. The idea is that our usual cosmological models assume a homogeneous universe for simplicity, but taking into account the inhomogeneity of matter density removes the need for a cosmological constant / dark energy.
Show threadAlavi | علویJan 5, 2025
@johncarlosbaez
Can't tell you how much I love your posts. Don't you put them in your blog or something? I think a lot of them are worth a blog post.
Show threadSteve DodgeJan 5, 2025

@johncarlosbaez
Those are choice words about the Higgs discovery! 😂

(In my circles, we call it the Anderson-Higgs mechanism. And the first observation of the Anderson-Higgs mode in a superconductor was in 1980, through Raman scattering!)

Show threadAli CaglayanJan 5, 2025
@johncarlosbaez I think another thing that ought to be mentioned is the brain drain that string theory has created in physics from the 80s onwards. This is of course all opinion, but a common saying I've heard is that big developments follow from funerals. There are some who believe that effort in physics is being misdirected at dead ends due to structural flaws in how academia works. I like mathematics and I do think string theory introduces interesting ideas, but it is not the kind of physics that was being practiced 70 years ago.
Show threadNick has moved to MathstodonJan 6, 2025
@alizter There was actually a recent thread by @johncarlosbaez that was sort of on what you're terming the string theory "brain drain".
Show threadJohn Carlos BaezJan 6, 2025

@internic @alizter - yes, I talked a bit about the causes of the Great Stagnation here:

https://mathstodon.xyz/@johncarlosbaez/113732200278292700

John Carlos Baez (@[email protected])

Attached: 1 image What's causing the Great Stagnation? Most branches of physics are thriving. But in so-called "fundamental physics" - briefly, the search for the ultimate laws of nature - we haven't seen a successful new theory since 1980. Why not? There are many causes. One is that string theory got a stranglehold on the market, crowding out other ideas. Another is that university bureaucrats are pressuring physicists to spend more and more time getting grants, which means following trends. But there's a third reason that is rarely discussed: physics is hard. Just kidding: we all know physics is hard. But quantum gravity in particular is hard, and people don't spend enough time talking about exactly why it's hard. First, physicists tend to assume that combining quantum mechanics, relativity and gravity will make us see strange new things when we probe down to a distance we get by combining Planck's constant ℏ, the speed of light 𝑐 and Newton's gravitational constant G. This distance, the 'Planck length', is about 10¹⁵ times smaller than what we can study now with particle accelerators. But a bunch of unexpected new stuff could happen long before we get down to the Planck length! Indeed we usually see surprises when we look at things 1000 times smaller than before. Second, physicists like theories that can be extrapolated to *arbitrarily small* distances. These are called 'renormalizable' quantum field theories. The quest for such theories led physicists to supersymmetry and strings. In these theories spacetime is a continuum - that is, it has no 'graininess' at small distances. We don't know this is true. Why don't we simply drop this assumption? Well.... (1/n)

Mathstodon
Show threadinkwater Jan 6, 2025
@johncarlosbaez @internic @alizter no mention of the biggest gorilla in the room wrt novel physics, inter/national security liabilities?
Show threadpenguin42Jan 5, 2025
@johncarlosbaez The years on this are interesting, some of these things I'd learned but hadn't realised they were that recent or old.
Show threadAndrew GallagherJan 5, 2025
@johncarlosbaez I’d be tempted to add the strong CP problem to your list. Sure, you can just *declare* that there is no problem, but it feels arbitrary, and symmetry has long been a reliable guiding principle of physics…
Show threadJohn Carlos BaezJan 6, 2025

@andrewg - my list is not a list of problems with existing theories. I do have an (outdated) list of open questions in physics:

http://math.ucr.edu/home/baez/open_questions.html

The strong CP problem should be there, but it's not! Heck, I'll add it right now, and put in more detail some other time.

Open Questions in Physics

Show threadHudJan 5, 2025
@johncarlosbaez The galaxies spinning faster than expected… I’m sure it’s those pesky parallel universes. But thanks for the history lesson. I am not a scientist and could still understand what you wrote.
Show threadJohn Carlos BaezJan 6, 2025
@hudsoch - great, thanks!
Show threadj_bertolottiJan 6, 2025
@johncarlosbaez I am missing the experimental evidence of black holes somewhere in that list. Not sure where one would put the exact date, but when I was a student it was still not obvious at all that black holes were real 🙂
Show threadJohn Carlos BaezJan 6, 2025

@j_bertolotti - Or maybe I should remove the items about gravitational waves, because once you start listing individual confirmations of a theory where do you stop? For the Standard Model, I only listed predictions and/or discoveries of new fundamental bosons and fermions, not any other consequences.

Black holes certainly are shocking. It's hard to say when they were shown to exist; when I heard about Cygnus X-1 I was convinced, but others needed to see redshifted spectral lines of stuff falling in, and some people still aren't convinced.

Show threadMatt McIrvinJan 5, 2025
@johncarlosbaez And the pop science news always emphasizes the papers making extraordinary claims that throw out huge chunks of theory: this or that does not exist. I'm always suspicious of these.
Show threadDeen AbiolaJan 6, 2025
@mattmcirvin @johncarlosbaez What are your thoughts on the recent timescape model news cycle, if you don't mind me asking.
Show threadMatt McIrvinJan 6, 2025
@metarecursive @johncarlosbaez I don't really understand the timescape model and haven't read the paper, so I can't comment intelligently on the merits, but it's the general kind of thing I approach with skepticism--it sounds almost like the "tired light" models sometimes put forth as alternatives to the Big Bang, which have a poor track record.
Show threadMatt McIrvinJan 6, 2025

@metarecursive @johncarlosbaez Specifically, while it's absolutely true that, from the perspective of an external observer, clocks tick slower in a gravity well, I have no idea how that could result in an illusionary accelerating expansion. It's just gravitational redshift. Gravitational redshift doesn't increase the further away something is. But maybe I'm missing something fundamental.

The last news cycle like this was "the dark energy is inside of black holes" and that didn't make any sense to me either, theoretically. I recall seeing Dr. Becky Smethurst saying she couldn't judge the theory but the observational argument wasn't convincing to her, so I didn't look much further into the theory.

Show threadMatt McIrvinJan 6, 2025
@metarecursive @johncarlosbaez The pop descriptions seem to imply that the idea in timescape is that light picks up extra redshift by passing through higher density regions where "time is slower", but... how does that work? Shouldn't it get blueshifted on the way in and redshifted on the way out? Maybe there's some asymmetry in an expanding universe that accomplishes the net effect, but I don't see it. Or maybe I've got the idea backwards. I probably need to read the original papers to have a better idea of what's supposed to be going on here.
Show threadMatt McIrvinJan 6, 2025
@metarecursive @johncarlosbaez ... thinking about it some more, maybe you could make it work with a "hierarchical" (aka fractal) distribution of matter like in some old approaches to Olbers' paradox. Inhomogeneities in the effective clock rate all the way up, and we happen to be in one of the densest sub-sub-sub-regions. But I'm just spitballing.
Show threadJohn Carlos BaezJan 6, 2025

@metarecursive wrote: "what are your thoughts on the recent timescape model news cycle, if you don't mind me asking."

This is the sort of pop science news I tend to ignore, because the pop descriptions make no sense and I figure if there's anything solid behind it I'll eventually hear about it from actual scientists, explained in a way I can understand.

But just for fun I'll see what Wikipedia says:

https://en.wikipedia.org/wiki/Inhomogeneous_cosmology#Timescape_cosmology

"In 2007, David L Wiltshire, a professor of theoretical physics at the University of Canterbury in New Zealand, argued in the New Journal of Physics that quasilocal variations in gravitational energy had in 1998 given the false conclusion that the expansion of the universe is accelerating."

So why the new hype? Oh, this:

https://arxiv.org/abs/2412.15143

Wikipedia says:

"One more important step being left out of the standard model, Wiltshire claimed, was the fact that as proven by observation, gravity slows time. Thus, from the perspective of the same observer, a clock will move faster in empty space, which possesses low gravitation, than inside a galaxy, which has much more gravity, and he argued that as large as a 38% difference between the time on clocks in the Milky Way and those in a galaxy floating in a void exists."

Bwahaha! That's a huge amount. I'd like to see how Wiltshire got that number.

The rate of time when you're sitting on a massive spherical object is about sqrt(1 - rₛ/r) the usual rate of time, where rₛ is the radius of a black hole of that mass and r is the actual radius of that object. For a neutron star rₛ/r ≈ 1/2 so this is about 70%, i.e. time is slowed by roughly 30%.

(1/2)

@mattmcirvin

Inhomogeneous cosmology - Wikipedia

Show threadJohn Carlos BaezJan 6, 2025

@metarecursive @mattmcirvin - Luckily Wikipedia points out that @startswithabang, who actually knows astrophysics, has written about the *new* timescape hype just 3 days ago:

https://bigthink.com/starts-with-a-bang/lumpy-explain-dark-energy/

So I recommend reading this, and now I'll do that.

(2/2)

Ask Ethan: Can a lumpy Universe explain dark energy?

Our Universe isn't just expanding, the expansion is accelerating. Instead of dark energy, could a "lumpy" Universe be at fault?

Big Think
Show threadStartsWithABang (old account)Jan 7, 2025

@johncarlosbaez @metarecursive @mattmcirvin

I love how non-experts see what I wrote and say, "big deal, this is just Ethan's old theory versus Wiltshire's new theory, and of course he's going to favor HIS theory!"

Whereas experts look at this and say, "oh, right, it's important to look at what's true and what's known conventionally, and how, and then compare that with the author's out-of-the-mainstream assertions."

Thanks John!

Show threadMatt McIrvinJan 6, 2025

@johncarlosbaez @metarecursive Thanks, I hate having to bend over backwards to try to make sense of one of these stories where there's a claim that doesn't sound like it makes any sense, but everyone acts as if it does so I have to try to figure out what's going on and if there's anything to this.

The claim that every conventional cosmologist is making an elementary mistake (ignoring the effect of gravity on clocks) should have been a red flag.

Show threadJohn Carlos BaezJan 6, 2025

@mattmcirvin @metarecursive - Wiltshire's new paper looks very sophisticated and like a typical sophisticated astrophysics paper you can't really tell what the basic ideas are. As @startswithabang points out, it's the latest in a long series. It's probably easier to debunk if you start with the first one:

https://arxiv.org/abs/gr-qc/0503099

and then see if anything has been fixed since then. It's too much work for me!

It's sad how much space in the pop science journalism ecosystem is taken up by flaky claims while really good work is not discussed. At least we've got some people like @startswithabang who take this endless flaky dribble as an excuse to teach people a lot of physics.

Viable inhomogeneous model universe without dark energy from primordial inflation

A new model of the observed universe, using solutions to the full Einstein equations, is developed from the hypothesis that our observable universe is an underdense bubble, with an internally inhomogeneous fractal bubble distribution of bound matter systems, in a spatially flat bulk universe. It is argued on the basis of primordial inflation and resulting structure formation, that the clocks of the isotropic observers in average galaxies coincide with clocks defined by the true surfaces of matter homogeneity of the bulk universe, rather than the comoving clocks at average spatial positions in the underdense bubble geometry, which are in voids. This understanding requires a systematic reanalysis of all observed quantities in cosmology. I begin such a reanalysis by giving a model of the average geometry of the universe, which depends on two measured parameters: the present matter density parameter, Omega_m, and the Hubble constant, H_0. The observable universe is not accelerating. Nonetheless, inferred luminosity distances are larger than naively expected, in accord with the evidence of distant type Ia supernovae. The predicted age of the universe is 15.3 +/-0.7 Gyr. The expansion age is larger than in competing models, and may account for observed structure formation at large redshifts.

arXiv.org
Show threadMatt McIrvinJan 6, 2025

@johncarlosbaez @metarecursive @startswithabang like I said, the one before this was the "dark energy is hidden inside black holes" one, where my immediate reaction was "that doesn't work, does it? I mean, Alan Guth was studying what amounted to a black hole full of dark energy way back in the 80s and it doesn't do that! The no hair theorem still applies, right? From the outside, it's just a regular black hole!"

But, again, it got all this hype.

Show threadJohn Carlos BaezJan 6, 2025

@mattmcirvin - there's an ecosystem of physics reporters who don't know physics and failed Skepticism 101.

Angela Collier has a nice video essay on "Gell-Mann amnesia": we know journalists are talking nonsense a lot of the time when they discuss our own topic of expertise, yet we too easily forget this when listening to them discuss things we're not experts on.

https://www.youtube.com/watch?v=wBBnfu8N_J0

@metarecursive
@startswithabang

Gell-Mann Amnesia and Michio Kaku

YouTube
Show threadMatt McIrvinJan 6, 2025

@johncarlosbaez Reminds me of that long stream of papers claiming positive results for reactionless space drives like the "EmDrive". If all you were reading were the headlines, you'd get the idea that there was increasingly solid consensus that this was real. If you read the actual papers, the results all contradicted each other and all they had in common was that they were right at the limit of sensitivity of the experiment, and when they improved the controls, they'd get another "positive" result that was marginal for the new controls, which would be touted as a replication.

Meanwhile, the theoretical justifications made no sense, and the discussions would spin off into wild science-fiction speculations about applications. Classic pathological science.

Show threadJohn Carlos BaezJan 6, 2025

@mattmcirvin - @gregeganSF used to be a reluctant expert on the EmDrive, starting when New Scientist put out a ridiculous article supporting it.

I used to enjoy battling crackpots, but soon we'll have Trump, Musk and RFK in power, so I consider that battle thoroughly lost.

Show threadMatt McIrvinJan 7, 2025

@johncarlosbaez @gregeganSF bullshit needs to be called out, regardless of who has the guns.

Physics is what I actually know something about but the "COVID lab leak hypothesis" gave me that "taking crazy pills" feeling: the way all the virologists and epidemiologists who seemed to actually understand the subject said one thing, and the cops and spies and military analysts said a different thing, and the papers all assumed the second category were the ones who were right because they know secret stuff, don't they?

Show threadMatt McIrvinJan 7, 2025
@johncarlosbaez @gregeganSF This also happens with UFO/mystery-drone stuff: military sources saying there's something real there get automatic credibility because of the assumption they know secret things we don't, but maybe some of them just have uncritical attitudes about UFOs.
Show threadMatt McIrvinJan 7, 2025

@johncarlosbaez @gregeganSF ...it used to frustrate me that it was so hard to explain why "pushing off of the quantum vacuum", as one of the shifting explanations of the EmDrive claimed it was doing, wasn't a thing.

(Regardless of how many virtual particles you use to describe it, the quantum vacuum is a Lorentz symmetric state, so it has no net momentum. If you were to push off of it, you'd have to give it some momentum, which means you're changing it to a state that has some momentum. Which means there are quanta in it now. You just made a normal rocket, maybe a photon rocket. Not a thing that pushes itself without emitting stuff.)

Show threadllewellyJan 7, 2025

@johncarlosbaez @mattmcirvin @metarecursive @startswithabang

Even if you know a reporter isn't an expert in an area you're also not an expert in, there's often not much you can do about it anyway. Yes, there are some topics where I have some idea of where to find sources that are likely to be better informed than a non-specialist reporter, but those topics are a small portion of the much wider range of topics from which exciting news articles come from.

Show threadJohn Carlos BaezJan 7, 2025
@llewelly - Wikipedia is pretty good, and usually points to sources, so I often go there to check facts.
Show threadMatt McIrvinJan 5, 2025
@johncarlosbaez I got into the field right after this and I was excited by all the ideas popping up as possible next steps: GUTs, supersymmetry, technicolor, quark components, inflationary cosmology, string theory. In hindsight it all seems like a kind of extinction burst.
Show threadJohn Carlos BaezJan 5, 2025

@mattmcirvin - is there such a thing as an "extinction burst" in biology: a false flowering right before the crash?

But yes, we grew up in the same era. As an undergrad I saw Witten giving lectures on GUTs and Hawking giving a talk on virtual black holes. The mood was cocky. Among mathematical physicists, the use of algebraic topology to understand anomalies was tremendously exciting.

Show threadMatt McIrvinJan 5, 2025
@johncarlosbaez It's from psychology: when you take away the reward for some behavior, at first you get an increase in the behavior apparently because the subject assumes they need to do it harder. Then they start to give up and the frequency drops off.
Show threadAndreas KJan 6, 2025

@mattmcirvin
Well, how is basic, fundamental research monetised?

Let's be honest a chance that you might a phone call inviting to gala diner in a Nordic country, is in today's hyper-commercialised HE environments a little bit underwhelming.

@johncarlosbaez

Show threadKris HardyJan 7, 2025
@yacc143 @mattmcirvin @johncarlosbaez Typically through government grants (NSF, HHS, DoD, etc.) for universities, or in national laboratories.
Show threadJohn Carlos BaezJan 8, 2025
@nonlinear - you didn't link your post to the one you're commenting on, so it's an orphan.
Show threadKris HardyJan 10, 2025
@johncarlosbaez Strange. It looks linked in my UI. I'm not sure how to fix that.
Show threadJohn Carlos BaezJan 10, 2025
@nonlinear - the only way to fix it is to repost it. Anyway, at least the 3 people you mentioned will have already had a chance to read it.
Show threadSimonJan 6, 2025

@mattmcirvin @johncarlosbaez yeah, pop science in the late 80s was full of the next big thing in fundamental physics, and that was a big part of me choosing theoretical physics for my undergrad.

Maybe if Hubble had launched a little earlier, and with working mirrors, I'd have chosen the astrophysics stream and been less disappointed.

Show threadBodhipaksaJan 5, 2025
@johncarlosbaez Thank you. This is an incredibly helpful overview.
Show threadBodhipaksaJan 5, 2025
@johncarlosbaez It's amazing that it's only 114 years since we discovered that atoms have nuclei!
Show threadTottsJan 5, 2025

@bodhipaksa @johncarlosbaez 1903, 1st powered flight. 65 years later, we are on the Moon

That always gets me x

Show threadBodhipaksaJan 5, 2025
@Geri @johncarlosbaez Yes, it seems like an incredibly fast rate of development. Then follows 53 years with no humans going beyond low earth orbit. We're a funny species.
Show threadWolf480plJan 5, 2025
@johncarlosbaez why not start with Coulomb and include 19th century though?
(half-joking)